Dental instrument.



P. H. SKIN NEE.

DENTAL INSTRUMENT.

APPLICATION FILED MAY5, 1911.

1,071,106. Patented Aug126,1913.

WITNESSES INVENTOR BY MM W ATTORNEY UNITED STATES PATENT orrron.

FRANK H. SKINNER, OF CHICAGO, ILLINOIS.

DENTAL INSTRUMENT.

To all whomz'i may concern Be it known that I, FRANK H. Sumner, acitizen of the United States, residing in the city of Chicago, county ofCook, and State of Illinois, have invented certain new and useful.Improvements in Dental Instruments, of which the following is aspecification.

This invention relates to instrumentsused in dental surgery and hasparticular reference to a device for removing the crown of a tooth.

The object of the invention is to provide an eilicient and convenientinstrument particu'larly adapted for this purpose, and one Which. willfacilitate the speedy removal of a crown Without subjecting the patientto pain or inconvenience, or without straining the tissues, membranesand nerves of the tooth operated upon.

\Vith the above-named objects in view my invention consists in the novelinstrument hereinafter described in detail, illustrated in theaccompanying drawing and particularly described in the appended claim.

In the drawing -Figure' 1 is a top plan view of substantially afull-sized instrument embodying my invention, together with a portionofa lower jaw with the secondmolar of which the instrument is shownengaged. Fig. 2 is a side view of the instrument in the same workingposition, both upper and lower jaws being shown in vertical section.Figs. 3 and 4: are similar views showing the instrument in difierentpositions. Fig. 5 is a plan View of a double or reversible instrument.Fig. 6 is a side or edge view of same.

In Figs. 1 to 1, inclusive, 2 and 3 represent a pair of jaw-bodiespivoted together on a pivot 41. through a compass-joint comprising apair of disks 5 and 6 on the jaw 3 and a single disk on the jaw 52 heldbetween the disks 5 and 6. In the jaw 3 is an elongated or oblongtransverse hole 8 through which passes a jaw-operating screw 9 that hasthreaded engagement at 10 with athreaded bore in the jaw2. The screw 9is provided with a thumb-piece 11 with the aid of which the screw may beconveniently manipulated to draw the jaws together upon or release themfrom the work. On the screw is a collar 12 which bears against the jaw 3and cooperates with the threads to move the jaws.

The bodies of the jaws, without the beaks,

Specification of Letters Patent.

Application filed May 5, 1911.

body of the tool or instrument.

Patented A11 26,1913.

Serial No. 625,390.

or the parts designated by the numerals '2 and 8, are substantiallyidentical with the body portions of hand-vise jaws. In the presentinvention these bodies 2 and 3 are extended by noses or beaks whichproject at angles from the body portions, so that the instrument, as awhole, minus the tips, is of elbow, form. Each nose or beak is also ofelbow form, the bends being in opposite directions and outwardlyrelative to the These elbows, noses, beaks or extensions are label-edfirst an outward bend, then an inward and downward bend, and is providedwith the inwardly or horizontally projecting wedge. T1113 formation ofeach aw forms a roomy space between the noses or beaks adapted toreceive the top or crown of a tooth while the wedges are operatlng atthe base of the crown. That isthe noses or beaks straddle the tooth evenwhen the wedge-edges are brought together under the base of the crown orbetween the crown and the root of a tooth. On the other hand, theelevation of the jaw-bodies above the working positions of the beaksshown in Figs. 1 to 4L and their inclination relative to the beaksplaces the body of the instrument substantially in line with the row ofteeth, particularly the upper row, when said body is alined between theupper and lower row of teeth, or between them lengthwise. The elevationand inclination of the jaw-body also affords the operator anunobstructed view of the tooth operated upon when viewed from the rearor front of the instrument and the straddle of the beaks, or spacebetween them, all'ords an unobstructed view from above.

17 represents, in Figs. 1 to 4 the lower jaw of a patient, 18 designatesthe root of a tooth crowned with a crown l9 cemented to a post or crownpin 20 secured or cemented in the root of the tooth.

21 represents the plane or line of juncture between the crown and theroot at which are shown placed the edges of the wedges 15 and 1% readyto be forced toward each other to crowd the artificial crown and naturalroot of a tooth apart. In Fig. 4: the crown is shown partly removed, orloosened from the root or post, after having turned the operating screwto draw the jaws toward each other. This operation of the instrumentneed not be appreciably felt by the patient, because the lateral strainsare balanced by the opposition of the wedges, and longitudinally of theaxis of the tooth the strains are likewise balanced by the action andreaction against the top of the root and bottom of the crown,respectively, divided to opposite sides ofthe crown pin or axis of thetooth.

In removing a crown from one of the innermost, or third, molars theinstrument may be operated without stretching the corner of the mouth orstraining the cheek, as the angle of the body of the instrument relativeto the beaks permits placing the instrument in line with the upper rowof teeth and substantially parallel with the tops of their crowns, and,as shown in Fig. 2, there is also room for operation of the thumbpieceof the screw when said piece is directed inwardly. In the modified formor double instrument shown in Figs. 5 and 6 any tooth may be operatedupon with the thumb-piece always outside of the mouth, as will appearmore fully in connection with the description of the double instrument.

In order to make it possible to place the thumb-piece of the screw inthe same relative position whether it be an upper or lower, right orleft tooth, I have provided the double form shown in Figs. 5 and 6. Inthis form by shifting the screw the thumb-piece may always extendoutwardly. The double instrument is composed of just as few members,pieces or stampings as the first-described instrument.

In the double form the jaws and beaks extend in duplicate to both sidesof the pivot in opposite directions, and these jaw-bodies are labeled 22and 23. The joint is substantially the same as that shown in Fig. 1,with the modification that the joint-disks 5, 6 and 7 carry two insteadof only one pair of jaws. In the double construction the holes for theoperating screw are duplicated, so that when the righthand end of theinstrument, as it appears in, say, Fig. 5, is used the screw is simplyremoved from the left-hand end where it is shown in full lines andinserted in the dotted line position shown to the right.

I claim as my invention In a dental instrument the COIIlblIlZLfiOIl witha pair of jaw-bodies pivoted together intermediate of their ends, ofpairs of elbows on the ends of said jaw-bodies, each said pair havingcooperating beaks thereon, each said pair of elbows extending from saidjaw-bodies oppositely to the angle of extension of the other elbows, andmeans for applying mechanical force to either of said pairs of elbowswith the aid of a single screw.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

FRANK H. SKINNER.

WVitnesses M. C. ALLEN, J. M. BECKSTROM.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

